An exhaust gas purification device is mounted in an exhaust gas pipe of an internal combustion engine such as a gasoline engine, a diesel engine, etc. The exhaust gas purification device captures particulate matter (PM) contained in exhaust gas emitted from the internal combustion engine, and collects the particulate matter.
The exhaust gas purification device has an exhaust gas filter for collecting particulate matter contained in exhaust gas. (See patent document 1 and patent document 2)
The exhaust gas filter disclosed in patent document 1 and patent document 2 has a plurality of cell walls and cells. Each cell is surrounded by the cell walls. The cells are composed of plugged cells and open cells. An end part at an upstream side of each of the plugged cells is plugged by a plug member. Each of the open cells is not plugged by a plug member. Pores are formed in the cell walls which are adjacently arranged between the plugged cell and the open cell so as to allow exhaust gas to flow between the plugged cell and the open cell. When exhaust gas is flowing through the pores formed in the cell walls between the plugged cell and the open cell, the pores trap particulate matter contained in exhaust gas so as to eliminate the particulate matter from the exhaust gas. In addition, patent document 1 has disclosed an exhaust gas purification device having a structure in which plural exhaust gas filters are arranged in series so as to increase particulate matter collection capability.